aspartimide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-03-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by HPLC area | Higher grades are also offered |
| Primary analytical method | Reversed-phase HPLC, UV detection | Frequently paired with mass spectrometry |
| Confirmatory technique | Electrospray mass spectrometry | Observed mass compared with theory |
| Storage temperature | Minus 20 degrees Celsius, dry powder | Sealed, desiccated, protected from light |
| Solution handling | Prepare fresh before use | Hydrolysis proceeds in aqueous media |
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
=== American Indian === Alaska Native Brotherhood Brotherhood of North American Indians - Founded by Richard C. Adams of the Delaware Tribe of Oklahoma on December 5, 1911, in Washington, DC. Membership was open to people of Indian blood. Those married to Indians, the President of the United States, the Commissioner of Indian Affairs, and other public officials could become honorary members, without vote. The Brotherhood advocated giving Indians the right to vote and granting them citizenship, the placement of Indian children in public school, more Indians working at the Bureau of Indian Affairs, and Indian representation in Congress. The national convention in Washington would elect 20 national chiefs, a Great Sachem, a Chief Historian, and a Great Chaplain. The Brotherhood collapsed in 1913. Daughters of Sacajawea - Organized in the 1920s, possibly as the New York City chapter of the Teepee Order of America. Both groups were founded by Red Fox Francis St. James, which created difficulties, as he was intolerant of Catholics and blacks, so Catholic Indians and those that had black ancestry opposed his groups. In 1926, Princess Chinquilla, a Cheyenne woman, was the "Great Sacajawea" of the group and worked with St. James to create an Indian cultural center in New York, but the project fell through. Loyal Order of Tecumseh - Founded by Arthur C. Parker as a society within the Society of American Indians to provide a common ground for those with greater and lesser degrees of Indian blood.
==== Anima and animus ==== Jung argued that the unconscious of every man contains a complementary feminine element (the anima) and every woman a complementary masculine element (the animus). Within these complementary elements exist an inherited collective image of 'man' and 'woman' respectively, which only becomes conscious in actual contacts with men and women. As such, these are archetypes of the collective unconscious. These counterparts come in part from this inherited collective image, but also partly through a person's contact with the opposite gender in their life (particularly their parental figures), and partly through the latent masculinity (for women) and femininity (for men) that a person experiences in themselves. Like the shadow, if a person rejects their anima or animus, it is more likely to be projected outwards.
Pennington was born on October 8, 1872, in Nashville, Tennessee, to Henry and Sarah Malony Pennington. Shortly after her birth, her parents moved to Philadelphia to be closer to her mother's Quaker relatives. She became interested in chemistry at the age of 12 after reading a library book on medicinal chemistry. She walked to the University of Pennsylvania and asked a professor for help with the terminology she did not understand. She was told to come back when she was older. She entered the University of Pennsylvania in 1890 and completed the requirements for a B.S. degree in chemistry with minors in botany and zoology in 1892. However, since the University of Pennsylvania did not grant degrees to women at this time, she was given a certificate of proficiency instead of a degree. Pennington received her Ph.D. from the University of Pennsylvania in 1895. Her thesis was entitled "Derivatives of Columbium and Tantalum." From 1895 to 1896, she was a university fellow in botany at the University of Pennsylvania. She was a fellow in physiological chemistry at Yale University from 1897 to 1899, and conducted research with Lafayette Mendel and Russell Henry Chittenden.
==== Australia ==== DET is considered a Schedule 9 prohibited substance in Australia under the Poisons Standard (October 2015). A Schedule 9 substance is a substance which may be abused or misused, the manufacture, possession, sale or use of which should be prohibited by law except when required for medical or scientific research, or for analytical, teaching or training purposes with approval of Commonwealth and/or State or Territory Health Authorities.
Sources: en.wikipedia.org
The two substrates of this enzyme are (S)-malic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are oxaloacetic acid, NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-malate:NADP+ oxidoreductase. Other names in common use include NADP+-malic enzyme, NADP+-malate dehydrogenase, malic dehydrogenase (nicotinamide adenine dinucleotide phosphate), malate NADP+ dehydrogenase, NADP+ malate dehydrogenase, NADP+-linked malate dehydrogenase, and malate dehydrogenase (NADP+). This enzyme participates in pyruvate metabolism and carbon fixation. This enzyme has at least one effector, hn.
Piperacillin is a broad-spectrum β-lactam antibiotic of the ureidopenicillin class. The chemical structure of piperacillin and other ureidopenicillins incorporates a polar side chain that enhances penetration into Gram-negative bacteria and reduces susceptibility to cleavage by Gram-negative beta lactamase enzymes. These properties confer activity against the important hospital pathogen Pseudomonas aeruginosa. Thus piperacillin is sometimes referred to as an "anti-pseudomonal penicillin". When used alone, piperacillin lacks strong activity against the Gram-positive pathogens such as Staphylococcus aureus, as the beta-lactam ring is hydrolyzed by the bacteria's beta-lactamase. It was patented in 1974 and approved for medical use in 1981. Piperacillin is most commonly used in combination with the beta-lactamase inhibitor tazobactam (piperacillin/tazobactam), which enhances piperacillin's effectiveness by inhibiting many beta lactamases to which it is susceptible. However, the co-administration of tazobactam does not confer activity against MRSA, as penicillin (and most other beta lactams) do not avidly bind to the penicillin-binding proteins of this pathogen. The World Health Organization classifies piperacillin as critically important for human medicine.
Jack Throck Watson (May 2, 1939 – September 3, 2016) was an American biochemist who was a professor of biochemistry and chemistry at the Michigan State University, where he was also director of the MSU Mass Spectrometry Facility. While at MIT, Watson developed a gas chromatography–mass spectrometry interface, known as the Watson–Biemann separator, that removes helium from the gas chromatograph column effluent, thereby allowing analysis of less volatile and more polar compounds. Watson later worked on methods for the structure elucidation of peptides and proteins using fast atom bombardment and matrix-assisted laser desorption ionization (MALDI) mass spectrometry. After retirement in 2006, he continued to work on his introductory mass spectrometry textbook and teach short-courses in mass spectrometry.
Sources: en.wikipedia.org
The process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions can occur in the gas phase. These processes are an important component of gas phase ion chemistry. Associative ionization is a gas phase reaction in which two atoms or molecules interact to form a single product ion. A ∗ + B → A B + ∙ + e − {\displaystyle A^{*}+B\to AB^{+\bullet }+e^{-}} where species A with excess internal energy (indicated by the asterisk) interacts with B to form the ion AB+. One or both of the interacting species may have excess internal energy. Charge-exchange ionization (also called charge-transfer ionization) is a gas phase reaction between an ion and a neutral species A + + B → A + B + {\displaystyle A^{+}+B\to A+B^{+}} in which the charge of the ion is transferred to the neutral. In chemical ionization, ions are produced through the reaction of ions of a reagent gas with other species. Some common reagent gases include: methane, ammonia, and isobutane. Chemi-ionization can be represented by G ∗ + M → M + ∙ + e − + G
During the production of incandescent filaments, recrystallisation of tungsten is significantly lowered by adding small amounts of thorium dioxide to the tungsten sintering powder before drawing the filaments. A small addition of thorium to tungsten thermocathodes considerably reduces the work function of electrons; as a result, electrons are emitted at considerably lower temperatures. Thorium forms a one-atom-thick layer on the surface of tungsten. The work function from a thorium surface is lowered possibly because of the electric field on the interface between thorium and tungsten formed due to thorium's greater electropositivity. Since the 1920s, thoriated tungsten wires have been used in electronic tubes and in the cathodes and anticathodes of X-ray tubes and rectifiers. The reactivity of thorium with atmospheric oxygen required the introduction of an evaporated magnesium layer as a getter for impurities in the evacuated tubes, giving them their characteristic metallic inner coating. The introduction of transistors in the 1950s significantly diminished this use, but not entirely. Thorium dioxide is used in gas tungsten arc welding (GTAW) to increase the high-temperature strength of tungsten electrodes and improve arc stability. Thorium oxide is being replaced in this use with other oxides, such as those of zirconium, cerium, and lanthanum. Thorium dioxide is found in refractory ceramics, such as high-temperature laboratory crucibles, either as the primary ingredient or as an addition to zirconium dioxide.
This so-called reconciliation bill is in fact a big retaliation bill—retaliation against AFGE and other unions for successfully standing up for our members and fighting this administration's illegal attempts to obliterate our federal agencies and the patriotic civil servants who run our federal programs. These provisions represent a direct assault on federal employees and their labor unions and will make it that much harder for federal agencies to recruit and retain the qualified employees they desperately need to serve the American public. The 2001 recipient of the Nobel Memorial Prize in Economic Sciences, Joseph Stiglitz, was asked about the OBBBA in an interview with Swiss Radio and Television (SRF) as to how he would describe the legislation, to which he had replied:
Johann Eduard Hari (born 21 January 1979) is a British writer and journalist. Until 2011, Hari wrote for The Independent, among other outlets, before resigning after admitting to plagiarism and fabrications dating back to 2001 and making malicious edits to the Wikipedia pages of journalists who had criticised his conduct. He has since written books on the topics of depression, the war on drugs, the effect of technology on attention span, and anti-obesity medication.
Sources: en.wikipedia.org
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.
The dry powder is commonly kept at minus twenty degrees Celsius, desiccated and away from light. Solutions are generally prepared fresh because they break down faster than the solid form.
Tandem mass spectrometry or enzymatic peptide mapping can establish residue order. A single intact mass value indicates composition and molecular weight but not always the precise arrangement of residues.
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.